After double clicking on a mesh I need to find out what is the centre of the mesh regarding to its boundary box
window.addEventListener("dblclick", function (event) {
var pickResult = scene.pick(scene.pointerX, scene.pointerY);
var mesh = pickResult.pickedMesh;
//var centerPosition = mesh.GetCenter(); <-- what is the center
});
Once you have the mesh, you can call mesh.getBoundingInfo
On a bounding info object you have a bounding box and a bounding sphere. The sphere provides the mesh center in local and world coordinates